Telephone-exchange system.



E. E. HINRICHSEN.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAY 22. 1917.

1,Q89,46?0 Patented Dec. 31, 1918.

entree erase PATENT OFFICE EDWARD E. HINRICI-ISEN, OF NEW YORK, N. Y.,

ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SY S'IEM.

Specification of Letters Patent.

I PatentedDec. 31, 11911.8,

Application filed May 22, 1917. Serial No. 170,306.

To all whom it may concern:

Be it known that I, EDWARD E. HINRICH- SEN, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems incorporating subscriber or trunk lines of diiferent character. Some of the modern telephone exchanges include manual subscriber and trunklines, and automatic subscriber and trunk lines, all terminating at the same exchange. In these systems it is necessary to realize the best 1'c' sults in the operation of the system, to provide equipment at the exchange for connecting a calling subscriber with either a manual or automatic substation or trunk line.

The general object of this invention is to provide equipment which may be employed for this purpose, relieving the operator of any need of exercising any discretion, or as little discretion as possible, in setting up a connection.

It is also an object of this invention to provide means for automatically causing the selection of particular parts of the equipment to be employed with a line of any kind when connection is made with such line. It is preferable to automatically bring into operation certain of the equipment employed The drawing illustrates diagrammatically a portion of a telephone system embodying this invention. q

There is shown in the drawing two telephone lines, A andoB. which extend fromsubscribers stations to a central oliice at which is located a cord circuit C, employed for interconnecting telephone lines. A trunk circuit 1) terminating in a jack at the central otlice extends to an automatic exchange E, at which exchange terminates a plurality of telephone lines, one of which is shown at F. The cord circuit C is also adapted to connect either of the telephone lines A and B to the trunk circuit D. The cord circuit C, when the calling end-thereof is connected with a telephone line similar to A and B, is adapted to automatically connect therewith a source of ringing current, and when the cord circuit is connected with a trunk circuit, similar to D, leading to an automatic exchange, an impulse sending device is connected with the cord circuit.

Referring now to the operation of the system shown in the drawing, it will be assumed that subscriber on line A initiates a call in the usual manner. The operator at the central otii'cethereupon inserts answering plug 5 into line jack 6, whereupon cut-off relay 7 and answering supervisory relay 8 are operated. The operator may now actuate the listening key (not shown), connecting the telephoneset (not shown) to the cord circuit. Upon being advised that the calling subscriber desires to be connected with another telephone line of a station terminating at the central office, for example, line B, the operator restoresthe listening key to normal position and inserts calling plug 15 into line jack 16. The n'iarginal relay 17, test relay 18 and cut-off relay 19 immediately operate. The marginal relay 17 is so constructed that it will attract its armatures when it is included in circuit with the winding of the cut-off relay 19, but will not attract its armatures when included in circuit with resistance 20, connected with a jack 21, in which the trunk circuit D terminates at the central ofiice. The operation of the cut-off relay 19 disconnects from line B the normally connected line relay thereof. The operation of relay 18 closes a break in the tip strand of thecord circuit and causes the lighting of calling supervisory lamp and the operation of relay 26 over a circuit from battery through the lamp 25, upper winding of relay I 26, normal contact of relay 27, contact of tripping relay 28, and the lower alternate contact of relay 18 to ground. The opera tion of relay 26 connects circuit leads '29 and 30 to the tip and ring strands of the'cord circuit C. In the meantime the operation of marginal relay 17 has disconnected an impulse sender to from the circuit leads :39 and 30, and has connected a source ot r 1 ngmg current through the winding of tripping relay 28 to circuit lead 30, and has also caused the operation of relay so, which connects battery to the talking strands of the cord circuit. The operating circuit for relay 36 may be traced from battery through the winding of-relay 36 and contact 37 of marginal relay 17.

Call bell 38 at the station on line B is actuated, due to ringing current from source 35, and in response to thissi'gnal, the sub-, scriber removes the receiver from the switchhook, causing the operation of tripping relay 2S. Relay 27 then operates over a circuit from battery through the lamp 25, upper winding of relay 26, upper winding of relay 27, and the lower contact of relay 18 to ground. Relay'28, in operatlng, establishes a locking circuit for itself which may be traced from battery through the lamp 25, contact 39 of relay 2-7 and the upper winding thereof, and the lower contact of relay 18 to ground. The establishment of this locking circuit also establishes a short circuit for theupper winding of relay 26, which now releases, disconnecting ringing current from line B. Upon the release of relay 26, the talking strands of the cord circuit are con-iplet'ed and calling supervisory relay 10 operates over a circuit from battery through the lower alternate contact of relay 36, winding of calling supervisory relay 40, the lower normal contactof relay 26, ring contacts of the calling plug 15 and line jack 16, over one side of the line B, through the station apparatus, back over the other side of line B, tip contacts of jack 16 and plu 15, upper alternate contact of relay 18 upper normal contact of relay 26, and the upper alternate contact of relay 36 to ground' Relay 10, inoperating, establishes a shunt circuit including resistance 60 for the lamp which is therebyetiaced. Upon the completion of the conversation the subscribers may restore the receivers to the switchhooks, causing the release of answering and calling supervisory relays '8 and +0, whereupon the answering and calling supervisory lamps and are lighted to furnish disconnect signals. The operator may now withdraw the plugs from the jacks rcstoring all apparatus to its normal condi tion.

If th operator at the central otlice had been advised that the calling subscriber A desired to be connected with a telephone line terminating in the automatic exchange E, for example, telephone line I the operator would then insert the calling plug 15 into jack :21 associated with trunk circuit D. Upon the insertion of the calling plug 15 intojack 21, relay 18 is operated as before, but. the marginal relay 17 does not now operate. The operation of relay 18 causes the operation of relay 20, in the, manner hereinbetore described, connecting circuit, leads 2%) and 30 t the tip and ring strands of the cord circuit. Relay 19 then operates over a circuit from battery through switch arm 50, terminal 51, lower winding of clectromagnet 52, ring contacts of jack 21 nd plug 15, lower alternate contact of relay 2G, circuit lead 30, contact 47 of marginal relay 17, winding ofrelay .49, contact [of the impulse sender (3, contact 48 of marginal relay 1T, circuit lead 29, upper alternate contact of relay 26, upper alternate contact of relay 18, tip contacts of plug 15 and jack 21, and the upper winding of relay 52, t ground. Upon the'operation of relay 49, slowrelease relay 55 is actuated, completing a circuit from battery through the middle alternate contact and lower winding of relay 26. lower winding of relay 27, con tact 56 of marginal relay 17, and the contact of slow release relay 55 to ground. Relay 27 thereupon operates, establishing a locking circuit. .for itself which may be traced from battery through the lamp 25, contact 39 and upper winding of relay :27, and lower alternate contact of relay 18 to ground.

- While the operation f relay 27, establishes a short circuit for the upper winding of relay 26, this relay does not release, for it is held energized over the hereinbet'ore traced circuit, which includes its lower winding.

With the apparatus in the condition just described the operator may actuate the impulse sender 46 to send the proper number of impulses over the trunk circuit D to cause the actuation of a selector M at the auto- ,matic exchange E, to select line F. This selector M comprises in part an electromagnet 52, switch arm 50. terminals 51-, 57 and 58, and wipers (35 and ($6 for extending the trunk circuit D to the selected line. the interruptions between the impulses are long enough in duration to cause the release. of the armature of relay -19. they are too short to permit the. slow release relay to let go its armature. Consequently relays 2G and 27 will remain energized while the impulses are being set over the trunk circuit D and the selection is 'being made at the automatic exchange. hen the selection is completed the selector switch arm rests on terminal 58 and interrupts the hcreinbefore traced circuit. which included this arm, so that resistance 59 is now included in the circuit. This resistance is so high that it will not permit suflicient current to flow through relay l9 to maintain the energization thereof. Consequently relay 4.9 releases -its armature, whereupon slow release relay in turn releases its armature. Upon the release of slow release relay 55, the circuit,

I sory relay +0.

--cuit C.

including the lower windings of relays 26 and 27, will be opened, whereupon relay 26 will release its armatures, disconnecting the impulse sender 46 from the talking strands of the cord circuit and completing, at its upper and lower normal contacts, breaks in the talking circuit. Relay 27 does not release, for it remains energized over a circuit which includes its upper winding. Upon the release of relay 26, calling supervisory relay 40 does not operate, for high resistance 59 is still in the circuit. As soon as this resistance is removed from the circuit calling supervisory relay 40 operates. Current for the operation of the calling supervisory relay it) is furnished from. the battery at the automatic exchange. It will be remembered that when the cord circuit was connected to the telephone line B, current for the operation of calling supervisory relay 40 was furnished from a battery located at the central ofiice. It will be seen, therefore, that when the cord circuit is connected with a manual subscribers telephone line, talking current is furnished from the central otfice, whereas, when the cord circuit is connected to the trunk circuitextending to an automatic exchange, talking current 'is furnished from a battery located at the automatic'exchange. I

The automatic apparatus at the automatic exchange D has, in the meantime, while the sender *6 was being operated and relays 49, 55 and 26 were releasing, extended the connection to telephone line F, so that the apparatus is in such a condition that ringing current may be connected with the trunk circuit D for causing the operation of the call bell (51 at the station on line F. This may be accomplished in any. well-known manner, for example, by the actuation of any ordinary ringing key associated with cord cir- This ringing key is, however, not shown. In response to the operation of the calling bell 61, the subscriber removes the receiver from the switchhook, whereupon relay (i2 is operated, closing its contact to remove the resistance 59 from the circuit which includes the limbs of trunk circuit D and cord circuit C and the calling supervi- This relay 40 now operates to efl'ace the calling supervisory lamp 25. I'pon the completion of the conversation the rest-oration ot' the receiver to the switchf hook by subscriber A causes the release of ans\\-'-e1'ing supervisory relay 8, whereupon answeringsupervisory lamp 45 lights, to indicatea disconnect signal. lVhen the called subscriber F restores the receiver to the switchhook relay 62 is deenergized, removing the short circuit of resistance 59, whereupon resistance is included in the circuit, thereby causing the release of calling supervisory relay 40. Calling supervisory lamp 125 is thereupon lighted to furnish a disconnect signal; the operator, observing the light condition of the two lamps and 45, may withdraw the plugs-from the jacks, whereupon all apparatus returns to normal condition.

\Vhat is claimed is:

1. In a telephone exchange system, the combination of a plurality of called lines of different character, a telephone line connector, machine ringing apparatus associated with the connector adapted to be connected to a called line through a portion of the connector, an impulse sender associated with the connector and adapted to be connected to a called line through a portion of the connector, and mechanism controlled by the character of the called line to which the connector is connected for selectively connecting the apparatus or the impulse sender to such called line.

2. In a telephone exchange system, the combination of telephone lines of different character, a line connector, machine ringing apparatus and impulse sending mechanism, and means controlled by the character of the line to which the connector is connected for determining whether the machine ringing apparatus or the impulse sending mechanism shall'be connected to the called line to which 'the connector is connected.

3. In a telephone exchange system, the combination of a telephone line, an auto matic selector connected to the telephone line, a jack in which the telephone line terminates, a cord circuit, a *alling plug connected to one end of the cord circuit for connecting the cord circuit to the telephone line, a circuit interrupter, means responsive to the connection of the cord circuit with the telephone line for connecting the circuit interrupter therewith, means including the circuit interrupter and contacts of the plug and jack for causing impulses of current to flow over the telephone line for operating the automatic selector, and apparatus operating when the selection is completed to automatically disconnect the circuit interrupter from the cord circuit.

4. In a telephone exchange system, the

combination of a telephone line, a source of current normally connected in circuit with the telephone line, an automatic selector connected to the telephone line operating in response to current impulses sent over the telephone line, a Jack in which the telephone line terminates, a cord circuit terminating at one end in a plug adapted to cooperate with the jack to connect the cord circuit and telephone line together, a circuit interrupter associated with the cord circuit, circuit leads adapted to connect the interrupter to the cord circuit, means responsive to the connection of the cord circuit with the telephone line to connect the circuit leads with the cord circuit, and appa 'atus operating automatically when the selection is completed to disconnect the circuit interrupter from the cord circuit.

5. In a telephone exchange system, a plurality of telephone lines, an automatic selector on one of the lines, a cord circuit, plug and jack switching mechanism for connecting the cord circuit to the telephone lines, a current impulse sender, means including portions of the cord circuit and a telephone line for placing the selector and the sender in operative association with each other, means for automatically interrupting'such association of the sender and the selector when the selective operation of the selector is completed, and apparatus for incapacitating the first named means for placing the sender and the selector in operative association when the cord circuit is connected to a line to which no selector isconnected.

6. In a telephone exchange system, the combination of a cord circuit, a common battery telephone line, circuit leads normally disconnected from the strands of the circuit, impulse sending means normally connected to the leads, machine ringing apparatus associated with but normally disconnected from the leads, means to disconnect the impulse sending means from the leads and'connect the machine ringing apparatus thereto when the cord circuit is connected to the common battery line, and means for connecting the leads to the strands of the cord circuit and to the line upon the connection of the cord circuit with the line.

7 7. In a telephone exchange system, the combination of a cord circuit, telephone lines of different character, circuit leads normally disconnected from the strands of the cord circuit, means to automatically connect the leads to the cord circuit when the cord circuit is connected to a telephone line, machine ringing mechanism and impulse sending mechanism, one normally connected to the leads and the other associated with the leads but normally disconnected therefrom, and means governed by the character of the telephone line to which the cord circuit is connected for determining the particular mechanism to be connected to the leads for a particular connection,

s. In a telephone exchange system, the combination of telephone lines of different character. a link circuit. asourcc of signaling current. impulsc sending mechanism, and means controlled by the character of the line with which the link circuit is conncctcd for dctcrmining whether the source of signaling current or thc impulse sending mechanism shall be connected thereto.

E In a telephone. cxchange system, the combination of a manual telephone line, a trunk circuit extending to an automatic exchange, a source of signaling current, inipulse scnding mechanism. a link circuit, and

means for connecting the source of signalmg current to the link circuit when the link circuit is connected with the telephone line and for connecting the sending mechanism to the link circuit when the link circuit is connected with the trunk circuit.

10. In a telephone exchange system, the.

link circuit with a telephone line to connect the, leads with the link circuit, machine ringing mechanism and'limpulse sending mechanism, one normally connectedto the leads and the other normally disconnected therefrom, and means governed by the character of the telephone line to which the link circuit is connected for determining the particular mechanism to be connected to the leads for a particular connection.

11. In a telephone exchange system, the combination of a link circuit, telephone lines of different character, circuit. leads normally disconnected from the link circuit, a relay operating upon connection of the link circuit with a telephone line to con- Ilit the leads to the link circuit, a source of ringing current and an impulse sending device, one normally connected with the leads and the other normally disconnected therefrom, and a relay governed by the character of the telephone line to which the link circuit is connected for determining whether the source of ringing current or the impulse sending device shall be connected to the leads for a particular connection.

12. In a telephone exchange system, the combination of a telephone line, an autoinaticselector connected therewith, current impulse sending apparatus for supplying impulses of current to operate the selector, a link circuit, means in the link circuit responsive to the connection thereof with the telephone line for placing the sending apparatus in operative connection with the selector, and means for automatically interrupting the' operative connection of the sending apparatus with the selector when the selecting operation of the selector is completed.

13. In a telephone exchange system, the combination of a telephone line, an automatic selector connected therewith. current impulse sending apparatus for supplying impulses of current to operate the selector, a link circuit, a relay in the link circuit energized upon the connection thereof with the telephone line for operatively associating the sending apparatus with the selector, and a relay in the link circuit responsive upon the completion of the selecting operation of the selector for automatically interrupting the operative association of the sending apparatus with the selector.

14. In a telephone exchange system, the ratus, and a second relay in the link circuit combination of a telephone line, an" autoresponsive upon the completion of the selnatic selector connected therewith respon lecting apparatus of the selector for causing sive to current impulses transmitted over the deenergization of the first relay there- 5 the telephone line, current. impulse sending by to disconnect the sending apparatus from 15 apparatus for supplying impulses of curthe telephone line. rent to operate the selector, a link circuit, a In Witness whereof, I hereunto subscribe relay in the link circuit energized upon the my name this 18th day of May A. D., 1917. connection thereof With the telephone line 10 for connecting therewith the sending appa- EDWARD E. HINRICHSEN. 

